1. Field of the Invention
This invention relates generally to an improved kit and related method of use for quickly and easily refilling a medication reservoir of a medication infusion pump, particularly such as an infusion pump of the type adapted for implantation into the body of a patient. More particularly, this invention relates to an improved syringe designed for use in combination with other kit components to facilitate rapid and safe refilling of the pump reservoir.
Medication infusion pumps are generally known in the art for use in delivering a selected medication to a patient in a scheduled or preprogrammed manner. In recent years, such infusion pumps have been developed in compact form adapted for implantation into the body of a patient. They are used to deliver a specific medication such as insulin to the patient in discrete (but essentially continuous) doses over an extended time period. An implanted infusion pump of this general type typically includes an internal medication reservoir which is often subjected (for safety reasons) to a storage pressure less than ambient body pressure (negative pressure) to prevent undesired leakage of the medication from the reservoir.
Other implantable pumps may use neutral or positive pressure reservoirs, although they are not deemed to be as safe as negative pressure reservoirs. Other components included in the device include a power source, a miniature pump, and associated electronic programmed control means for delivering the medication to the patient according to a prescribed schedule. For one illustrative example of an implanted or implantable medication infusion pump of this general type, see U.S. Pat. No. 4,573,994, to Fischell.
Implanted medication infusion pumps are normally equipped with an inlet port through which fluid medication can be supplied to permit periodic refilling of the pump reservoir. This inlet port is typically positioned and shaped for receiving a transcutaneous needle through which the fluid medication is supplied from outside the patient's body. Accordingly, the pump reservoir can be filled or refilled without requiring surgical removal from the patient's body, and further without requiring any other significant surgical procedure.
While implantable, refillable medication infusion pumps constitute a major step forward in reliable and convenient administration of certain medications, devices and methods for periodically refilling the pump reservoir have been relatively complex and/or difficult to use such that refilling procedures have not been optimized, particularly with negative pressure reservoir devices. More particularly, syringe implements having a standard barrel and plunger have been used in combination with an appropriate transcutaneous needle to access the pump reservoir, with plunger retraction or advancement respectively aspirating residual medication from or supplying fluid medication into the reservoir.
Unfortunately, it has often been difficult to hold such syringe implements securely and safely while applying sufficient manual force to manipulate the syringe plunger. As a result, in the past, refill procedures have required a relatively high level of skill and have proceeded at a relatively slow pace. Moreover, it has normally been required for fluid medication to be degassed immediately before injection into the pump reservoir, such that the presence of relatively costly and sophisticated degassing equipment has also been required.
The present invention provides a relatively simple and easy-to-use kit for quickly and easily delivering fluid medication to the reservoir of an implanted infusion pump, wherein the improved kit provides effective and simple means for degassing the fluid medication. Moreover, the present invention provides for rapid and safe aspiration of residual medication prior to reservoir filling. In either case, the invention provides an improved aspiration or refill syringe adapted for drawing or delivering medication without requiring concurrent manipulation of a syringe plunger.